Richard Westbrook walked away unscathed following the biggest accident of his career Tuesday at Daytona International Speedway. (Photo: M. Stahlschmidt/Sideline Sports Photography)

Testing for Daytona Prototypes, P2 and Prototype Challenge cars was suspended Wednesday at Daytona International Speedway on the grounds of safety, due to a number of tire-related incidents, two of which caused airborne accidents for newly upgraded DPs.

According to IMSA VP of Competition & Technical Regulations, Scot Elkins, the decision to ground all prototype machinery, except for the DeltaWing coupe, was a joint decision with partner Continental Tire, as they work to come to the bottom of the issue.

The Englishman’s No. 90 Spirit of Daytona Corvette DP suffered an unidentified failure while braking into the high-speed Turn 1 section on the 3.56-mile oval/road course, sending the car airborne and into a series of rolls, according to multiple eyewitness.

It was a case of mixed fortunes for Fernando Alonso in Austin as he secured second place in the driver’s championship but saw Ferrari lose ground to Mercedes in the battle for second in the constructors’ version.

Alonso had a typically feisty race in Austin, eventually finishing fifth.